Isolation of <em>Erwinia amylovora </em>Bacteriophage from Soil and Pear Trees Plant Tissues

Abstract

Attributed to a Gram-negative bacterium, identified as Erwinia amylovora, the fire blight disease, recently detected in Tunisia, has become a real threat to our economy and our arboriculture. There is no effective curative treatment to eliminate the installed bacterium. It is therefore essential to prevent attacks and to limit the spread of the bacteria if it is already present. To do so we have chosen the biocontrol by bacteriophages. In this work we have isolated new strains of Erwinia amylovora (10 strains) from plant tissues where fire blight symptoms are persistent. These strains have been the subject of a molecular study. The isolated phages (30 isolates) were studied for their infectivity on Erwinia amylovora isolates and showed a surprising effect. Our phage isolates formed plaque of different sizes, with a diameter ranging between 0.8 and 7 mm on the soft agar layer containing the test bacterium. The phages thermostability showed that all these viruses resist at 80 ° C for 45 min.